jeuclid-cli: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/jeuclid-cli - from package: jeuclid-cli

You may install the required package with command apt-get install {package}
Error in other languages:
jeuclid-cli: bevel nie gevind nie
jeuclid-cli: comandă negăsită
jeuclid-cli: comando não encontrado
jeuclid-cli: commande introuvable
jeuclid-cli: command not found
jeuclid-cli: käsku ei ole
jeuclid-cli: không tìm thấy lệnh
jeuclid-cli: komanda nerasta
jeuclid-cli: Kommando nicht gefunden.
jeuclid-cli: kommandot finns inte
jeuclid-cli: komut yok
jeuclid-cli: nie znaleziono polecenia
jeuclid-cli: níor aimsíodh an t-ordú
jeuclid-cli: no se encontró la orden
jeuclid-cli: no s'ha trobat l'ordre
jeuclid-cli: opdracht niet gevonden
jeuclid-cli: parancs nem található
jeuclid-cli: perintah tidak ditemukan
jeuclid-cli: príkaz nenájdený
jeuclid-cli: příkaz nenalezen
jeuclid-cli: команда не найдена
jeuclid-cli: командата не е открита
jeuclid-cli: 命令找不到
jeuclid-cli: コマンドが見つかりません